The present invention generally relates to integrated circuits (IC), and more particularly to fabricating IC chips having a programmable shelf life.
New IC technologies may include individual IC chips (i.e., “dies”) arranged into a three dimensional integrated circuit, also known as a three dimensional semiconductor package (3D package). One type of 3D package may include two or more layers of active electronic components stacked vertically and electrically joined with some combination of through substrate vias and solder bumps. Current IC chips may never expire, they may exhibit a long lifespan and may even last forever if not powered up.
To continue the miniaturization trend in current IC technology, copper (Cu) metallization may be extensively used due to its low resistivity and high migration resistance. Owing to the rapid diffusion of copper into silicon (Si) and silicon dioxide (SiO2), copper structures may be covered with barrier metals and barrier insulators to prevent degradation of the IC. In the presence of oxygen and at relatively low temperatures, copper may act as a catalyst during the oxidation of silicon to form silicon dioxide.